Our invention relates generally to electric lamps and particularly to discharge lamps. More particularly, our invention pertains to a base assembly which makes up a discharge lamp in combination with a discharge lamp assembly. Still more particularly, our invention features provisions in such a lamp base assembly for preventing an electric discharge between a pair of conductors extending through the base structure of the lamp base assembly.
The discharge lamp, sometimes referred to as gas discharge lamp, vapor lamp, etc., has been known and used extensively in which light is produced by an electric discharge between electrodes in a gas (or vapor) at low or high pressure. Essentially, the discharge lamp may be thought of as a combination of a lamp assembly and a base assembly. The lamp assembly comprises a discharge lamp unit with a pair of lamp lead wires extending therefrom. The base assembly comprises an insulating base structure with a pair of conductors extending therethrough, and a pair of base leads serving as both electrical and mechanical connections between the conductors and the lamp leads.
There has been a problem left unsolved with the discharge lamp. It is essential for the proper functioning of the discharge lamp that an electric discharge should take place only between the electrodes within the lamp envelope. Unless properly insulated from each other, however, the pair of conductors extending through the lamp base structure has been most likely to develop a discharge.
Hitherto, as far as we are aware, the pair of conductors has been insulated from each other by filling the hollow base structure with a plastic after this base structure has been molded with the conductors received in position therein. We object to this conventional solution because, unavoidably, the plastic filler that has been allowed to solidify within the preformed base structure develops interstices of microscopic dimensions. Such minute interstices are easy to create discharge paths between the conductors. Moreover, once a discharge has taken place through such interstices, the plastic filler has become carbonized along the discharge path. The carbonized path has made easier the occurrence of another discharge. Thus the useful life of the conventional discharge lamps has sometimes be shortened even though the lamp units themselves may be faultless.